Motive power unit for model railroads and the like



Jan. 5, 1965 J. H. HAHN 3,164,106

MOTIVE POWER UNIT FOR MODEL RAILROADS AND THE LIKE Filed Oct. 9, 1961 f grl 26 2 so 66 6 Z B 56 68 INVENTOR.

JAMES H- HAHN ug Qw q/g d United States Patent MOTWE rowan This invention relates to a motive power unit for model railroads, and more particularly to a simple and inexpensive form of power transmission for model railroad m0- tive power units.

Generally speaking, the subject invention comprises a distinct improvement over the well-known rubberband drive systems for model railroad locomotives principally in the forms of: a single extensible flexible belt drive made of a helically coiled metal or a web of resilient plastic and bighted about the drive shaft and about a plurality of wheeled axles of a truck assembly; fair lead (funnel) guide means surrounding the drive belt between the drive shaft and the truck assembly and serving essentially as a ball and socket pivot joint between the locomotive unit and its truck assembly; and preferably a jack shaft and fly wheel combination for actuating the novel drive belt system by means of a high-speed, low-torque motor drive.

- Additionally, the drive shaft is provided with a pulley disc having V-notched recesses therein and the driven wheeled axles are correspondingly provided with V-notched recesses such that vastly improved drive characteristics and simulation of actual railroad operation are achieved. By incorporating the aforementioned principal features into the drive system of a scale model locomotive, it is feasible to use an inexpensive high-speed, low-torque prime mover and still obtain the operating characteristics desired in scale-model locomotive units.

In the prior rubberband drive systems, as exemplified by the teachings of United States Patent No. 2,903,974, issued to Robert M. Smith on September 15, 1959, a flexible drive belt comprising a rubberband is bighted under tension about a constant diameter drive shaft and about a reduced diameter portion of a singular wheeled axle. A low-speed, high-torque motor is required to rotate the shaft, which in turn rotates the rubberband drive belt. The essential operating feature of this prior art drive system resides in a slippage of the rotating shaft relative to the heatsensitive rubberband drive belt until the inherent adhesive power of the rubber is developed by frictional heat, at which time the belt begins to turn under the influence of the rotating drive shaft. This initial startup results in an undesirable and unrealistic jerking of the locomotive unit.

The slippage characteristics of the rubberband-type drive and the required utilization of a low-speed, hightorque motor to effect the desired drive have resulted in a locomotive operation which lacks the simulated realism of actual railroad structures which hobby enthusiasts strive for. Moreover, the tension under which the rubber band belt must be placed results in undue loads upon the motive source and in excessive friction and heat development at the bight points which tends to rapidly wear out the rubberband and thus to cause frequent breakdowns and necessities for repair.

Also, the rubberband belt tends to set during storage 2 axle is present in the. locomotive, as is invariably the case in scale model railroad equipment,the various rubberbands which are required must be very carefully matched and selected for co-active operation, since otherwise one rubberband will exhibit a tendency to impede the drive of another and thus to give poor pickup and running char acteristics, especially on curves, switches, graded inclines, or other irregularities in the guiding tracks of the model railroad system.

It is a primaryobject of this invention to obviate the aforementioned difficulties exhibited by the prior art rubberband drive systems and to present an improved drive system for scale model locomotives which is characterized by case of assembly and disassembly; by more realistic simulated characteristics of actual railroad operation without the need for expensive transformers to simulate gradual stop and start and incline ascending railroad characteristics; by inexpensive motive power means; and by increased driving ability per drive belt by virtue of the ability to utilize high-speed, low-torque motor structures with appropriate speed reductions so that one drive belt can drive two or more wheeled axles. I

These and other objects, advantages, and features of this invention will hereinafter appear, and for purposes of illustration, but not of limitation, an embodiment of the invention is shown in the accompanying drawing, in which:

FIG. 1 is a side elevational view of a scale model locomotive constructed in accordance with the teachings of this invention and schematically showing the drive system in phantom lines;

FIG. 2 is a top plan view of the locomotive of FIG. 1 with the decorative carriagehousing removed;

FIG. 3 is a bottom plan view of the locomotive of FIG. 1; and

FIG. 4 is a side sectional view taken along the line 4-4 of FIG. 2, showing the details of construction for the drive system. I

In FIG. 1, the reference numeral 1 generally indicates the novel scale model locomotive. The locomotive scale model unit 1 comprises a decorative carriage housing 2 which is a scaled-down version of an actual railroad locomotive, a main frame 4 supporting the housing'Z, and truck assemblies 6 and 8 which maintain the main frame 4 and its attached components in spatial relationship above the tracks it of the scale model railroad. The drive system for the locomotive unit 1 comprises an electric motor 12 positioned on the main frame 4 and gear drive means 14 actuated by the electric motor 12 to rotate a drive shaft 16 which is rotatably iournaled within the main frame 4 and which in turn drives the truck assembly 8, in a manner to be subsequently described.

In more specific detail, the electric motor 12, which preferably comprises a high-speed low-torque electric motor, actuates a motor shaft 20 to which is rigidly affixed a drive gear 22. Jack gear 23, rigidly secured to drive shaft 16, meshes with the drive gear 22 in order to rotate the drive shaft 16 at a reduced speed relative to the rotation of the motor shaft 2%. The drive shaft 16 is rotatably journaled within the main frame 4 as by positioning the ends of the shaft 16 in the bearing grooves 28, 32, of the bearing supports 26, 30 respectively. Preferably, the drive shaft 16 is journaled for free floating rotation relative to the main frame 4- whereby axial displacement of the drive shaft 16 relative to the frame 4- may be efiected.

A dead weight housing 29 is located on the main frame 4 and is positioned such that the drive shaft 16 may rotate or axially displace within the grooves 25 and 25a oppositely disposed on the top of the housing 29. The dead Weight housing 29 has a hollow interior 27 which surrounds both the bearing support 30 and an aperture 60 located in the'base of the main frame 4. A dead weight cartridge 18 may also be secured 'to te main frame-4 in order to provide the desired overall weight distribudrive belt 36, in a manner to be subsequently described.

The disc 34 is located on the drive shaft 16 in alignment with the aperture 6% of the main frame 4 so thatthe drive belt Edwhich depends from the pulley disc 34 may ena fair lead funnel 58 comprising an inverted bell-shaped funnel having a bottom diameter 68 and a narrower top diameter 6 6.

The aperture dd of the main frame 4 is surrounded by a rectangular housing 62 which contains a circular opening 64 dimensioned to receive the top diameter portion 66 of the fair lead funnel 553. It is apparent that the truck assembly 8 with its attached fair lead funnel 58 may be positioned adjacent the main frame 4 by locating the fair lead funnel 58 within the aligned open- 7 ings provided by theaperture 6i and the opening 64such that the truck assembly 3 may be displaced both vertically and angularly relative to the main frame 4.

Metallic leaf springs 41 are positioned adjacent the side plates 40 of the truck assembly 8 by placing the springs 41 within the slots'43 located near the respective ends of the cross bolster plate 42 adjacent to the junction points where the bolster plate 42 and the side plates 40 are joined. The slots 43 may be dimensioned to securely seat the springs 41 therein without any additional attachments, or the springs 41 can be joined to the bolster 42 by conventional mechanical fasteners, The springs 41 are provided with detnts 44 suitable for receiving the tapered ends 46 of the axles 47 which extend at either end of the truck assembly 8 between the parallelly aligned leaf springs 41. In the preferred embodiment of the invention, the springs 41 are constructed from a berylliumcopper alloy to aiford the desired resiliency and to provide a currentcarrying capacity, for purposes to be subsequently described.

The axles 4'7 have wheels 50 rigidly secured thereon for rotation with the axle 47. The wheels t) are provided with flanges 52 for engagement with the tracks in a well-known manner.

I Betweenthe wheels 5!}, an enlarged diameter portion 48 for the axle 47 is provided. The composite structure of the enlarged diameter portion 48, the wheels 50, and the concentrically disposed axle 47 with its tapered points 46 is hereinafter referred to as the wheeled axle'45. This composite wheeled axle 45 may be secured between the side plates 40 of the truck assembly 8 by suitable deflection-of the leaf springs 41 such that the tapered points 46 of the axle 47 may be received within the detents 44 of the leaf springs 41. It is thus apparent that the wheeled axle 45 may be easily inserted and removed by a simple snap-in or snap-out movement relative to the truck assembly 8. The wheeled axle 45 is adapted for rotation relative to the truck assembly 8 by the bearing journaling of the taper points 46 within the detents 44.

A The enlarged diameter portion 43 of the wheeled axle 45 is provided with a V-notch 54 at the central portion thereof. The drive beltfiis rigidly seated within the V-notch 54 of at least two wheeled axles 45 each rotatably suspended within a trucl: assembly 8. The drive belt 36 is thus bighted about at least twowheeled axles at its one end and bighted about the pulley disc 34 of the drive shaft 16 at its other end. In order to accommodate the different directions of rotation of the pulley disc 34 and the Wheeled axle 45, the drive belt 3-5 is quarter-turned between its respective bight contacts. As best seen in FIG. 4, the portion of the drive belt 36 which extends between the bight portions surrounding the pulley disc 34 and the wheeled axles 45 feeds through the fair lead funnel 58, thereby securing the truck assembly 8 with its fair lead funnel 58 within the main frame 4 in a pivotable joinder.

in the preferred embodiment of this invention, a fly wheel 15 is attached to the motor 12 via a fly wheel shaft 13 to aid in the operation of the locomotive unit 1, in a manner to be subsequently described.

The operation of the assembled scale model locomotive can be described with reference to the truck assembly 8. The wheels 5% riding on the tracks to conduct current therefrom through the axle points 46 and into the conductive leaf springs 41. Vires (not shown) are suitably attached to springs 42 and lead to the motor 12, which is thereby energized. The energization of the motor 12 rotates the shaft 2t; and its attached drive gear 22 in a direction determined by the polarity of the motor and the current fed thereto. The gear 22 in turn rotates the jack gear 23 which turns the drive shaft lb rigidly attached thereto. As the drive shaft 15 rotates, the pulley disc. 34 rigidly secured thereon likewise rotates, and the drive belt 36 bighted around the pulley disc as is caused to rotate, thereby rotating the wheels 56: in a given direction.

This drive sequence is accomplished without any slippage characteristics of the drive belt 36 relative to either the drive shaft 16 or the wheeled axles 45. The drive belt 35 is quarter turned so that the wheels will rotate in planes perpendicular to the plane of rotation of the pulley disc 34 when the respective V-notch 35 on the pulley disc 34 and the V-notches 54 on the wheeled axles 45 engage the drive belt 36 firmly grooved therein. These V- notches are preferably of a trough-shape cross-sectional configuration, the bottom portion of which is less in width than the diameter of the drive belt 36 so that the drive belt 36 will not slip relative to the V-notched grooves but is rather securely positioned therein by a biting action of the drive belt 36 into the side and preferably also the bottom walls of the V-notches. A disposition of the side walls at .an angle of from 10 to 15 degrees from the vertical has been found most desirable when operating with a metallic helical coil as the drive belt 36.

Apparently, a very slight tension in the helical coil provides a series of bite teeth comprising each of the adjacent curved portions of the helix which, upon slight movement of the belt 35 relative to the V-notches, firmly grasp the surfaces thereof and rotate the member containing the V-notch Without any significant relative slippage.

The drive sequence is thus smooth and continuous within the truck assembly 8 and no significant slippage occurs between the belt 36 and either the pulley disc 34 or the whee-led axles 45. The fact that the belt 36 is bighted around more than one axle 43 further serves to minimize any slippage of the belt as within the truck assembly 8. Whatever slippage is involved in the locomotion of the scale model unit 1 is transferred from within the drive system (as in the prior art rubberband drive) to a slippage of the wheels 54} relative to the tracks 10, which characteristic simulates to a marked extent the driving characteristics of an actual full scale railroad locomotive.

The fair lead funnel 53 serves the dual functions of guiding the belt 36 as it rotates between the drive shaft 16 5. a r other may be readily effected without disturbing the drive operation. In this fashion a free floating ride is observed which further aids in the marked simulation of the actual operating characteristics of a railroad operation and which likewise serves to minimize the possibilities of derailment. However, even if derailment should occur, the tracks are unlikely to be shorted out by virtue of the minimum of metal parts which have to :be utilized in the truck assembly 8. Thus, only the wheels Stl, the axle 47, and the springs 41 need he of metal, the remainder of the truck assembly 8 being constructed of plastic or other suitable non-conductive material.

It should also be noted that the free floating axially displaceable disposition of the drive shaft 16 relative to the main frame 4 also facilitates the desired freedom of mobility for the truck assembly 8 relative to the main frame 4. It has been found that the combination of this free floating disposition of the shaft 16, which of course provides for a variable disposition of the bighted end of the belt 36 about the pulley disc 34 relative to the main frame 4, coupled with the free floating connection of the truck assembly 8 to the main frame 4, provide an overall operation which closely approximates and simulates the drive characteristics of an actual railroad operation and which enable the locomotive unit 1 to be operated with a minimum of wear and tear and necessity for repairs. Thus the horizontal bounce and vertical sway of the assembled scale model unit 1 approximate the corresponding characteristics of an actual railroad locomotive, especially when the unit .1 passes over inclines, curves, switches, or other irregularities in the track system.

The motor 12, as described, is a high-speed, low-torque motor which is of a well known inexpensive type. The free floating jack drive effects a speed reduction of the shaft 16 via the meshed reduction gears 22, 24. Moreover, a dual speed reduction is involved in that the drive belt 36 itself effects a further speed reduction for the.

wheeled axles 45 by virtue of its engagement with the enlarged diameter portions 48 thereof such that the overall operation yields excellent start and stop characteristics. The free floating speed reduction for the high-speed, lowtorque motor 12 allows a motor operation in its most efiicient range and current consumption can be out almost in half, as compared to the conventional motors utilized with rubberband type drives. Practically no load is impressed on the motor bearings, and a smoother and more reliable drive is exhibited. Also, the incorporation of the fly wheel 15 provides inertia to carry the locomotive unit 1 over irregularities in the track structure, such as curves, inclines or switches.

It is preferred that the drive belt 36 be bighted around more than one of the wheeled axle-s 45 in order to minimize slippage and frictional dissipation of energy, as previously described, and further in order to drive more wheels per belt, and, since hunting of the belts along the drive shaft is eliminated by virtue of the V-notch construction, it is possible to construct a scale model locomotive having a maximum of driven wheels for a given size. This feature is especially desirable where an incline climbing locomotive is desired.

Thus, more than one truck assembly 8 may be provided on a main frame 4, as desired, by suitable dimensioning of the locomotive unit 1. :T he drawing shows an idler truck 6 which is merely journaled for angular rotation relative to the main frame 4- as 'by the conventional screw attachment 7 9, but of course this idler truck assembly 6 could be readily adapted for replacement by another motive truck assembly 8 which functions in the manner previously described.

While the construction has been described with reference to a helical metallic coil as the drive belt 36, it should be understood that other types of belts may be utilized. For example, it has been found that endless bands of certain resilient plastics, such as polyformaldehyde, polytetrafluorethylene, nylon, and the like are sufficiently rigidto bite. into the V-notches of the split sheave pulley system and thus to exhibit the desired non: slip characteristics even when externally lubricated in ad dition to the inherent slippery characteristics of the specified materials. Correspondingly,,it has been found that the pulley disc 34, the axles 48,,or the fair lead funnel 58 may be constructed of similar materials. It is especially desirable to intercombine the materials as by com structing the belt 36 of metal and the axles 45, pulley disc 34, and fair lead funnel 58 of thedescribed resilient plastics or vice versa in order to achieve the most positive non-slipping drive system.

Also, while a unitary H-shaped frame has been described for the truck assembly, it should be understood that the fair lead funnel guide and joinder structure could be located atop a multi-directional resiliently deformable truck assembly of the type described in the copending patent applications entitled Improved'Tnrck Assembly for Model Railroads, Ser. No. 143,904, filed October 9, 1961.

It should be apparent that a novel and improved scale model locomotive has been described which obviates the deficiencies of the prior art rubberband type drives and which is characterized by the desired simulation of actual railroad operation at a minimum of expense and at a understood that various changes and modifications may be made in the'details of construction, arrangements, operations, and materials for the various elements without departing from the spirit and the scope of the invention, especially as defined in the appended claims.

What is claimed is:

1. In a vehicle for scale model railroads, the combination with an elongated frame having a longitudinal axis in the direction of motion of said vehicle, a truck assembly supporting said frame in spatial relation above track of said scale model railroad and comprising a plurality of wheeled axles, said frame having an opening therein extending therethrough and over said truck assembly;

of an electrically energized motive power unit comprising a high-speed low-torque electric motor supported on said frame,

a drive shaft rotatably journaled on said frame,

mechanical coupling means interconnecting an output shaft of said motor to said drive shaft for communicating motive power thereto,

linking means connecting said drive shaft to one of said wheeled axles for transmitting power from said drive shaft to said wheeled axles,

said linking means comprising an endless drive belt bighted about said drive shaft and about said one of said wheeled axles,

and fair lead means comprising a bell-shaped upstanding inverted funnel secured to and supported at its base on said truck assembly and extending upwardly through said opening in said frame and into a housing surrounding said opening and extending thereabout,

said fair lead means providing low friction guide means for guiding the movement of said belt bighted about said drive shaft and one of said wheeled axles and constituting a mobile ball and socket type floating joinder of said truck assembly and the said frame to pivotally connect said truck assembly and said frame.

2. The motive power unit of claim 1 wherein said mechanical means connecting said output shaft to said motor comprises coupled speed reduction gearing, and wherein the endless belt comprises an extensible metallic helix, and wherein the drive shaft has a belt-receiving notch therein and the axles each have belt-receiving notches therein, the said notches each having a troughshaped cross-sectional configuration, the bottom portion of which is less in width than the maximum diameter of 3, 1 ear-es the 'endless belt, whereby the bighted beltis tensioned within thesaid trough-shaped notches'for nonslipdriv ing of the said Wheeled axles.

.3. Thernotive power unit of claim 1 wherein the endless belt comprisesa band of substantially inextensible resilient plastic and wherein the drive shaft has a belt receiving notch therei'n' and the axles each have beltreceiving notches therein, the said notches each having a trough-shaped cross-sectional configuration, the bottom portion of which is less in Width than the maximum diameter of the endless belt, whereby the bighted belt is tensioned Within the said trough-shaped notches for nonslip driving of the said Wheeled axles.

4. In a vehicle for scale model railroads, the combination with an elongated main frame having a-longitudinal axis in the direction of motion of said vehicle, and a truck assembly comprising a plurality of wheeled axles, and means supporting said frame in spatial disposition above tracks of said scale model railroads, of adrive system for propelling saidvehicle along said tracks,

said drive system comprising a high-speed low-torque electric motor supported on said frame, a drive shaft extending above and lengthwise of said frame and rotatably journaled thereon, coupling means connecting said drive shaft to a driven shaft of said motor, u said coupling means comprising a speed reduction gear system connecting said driven shaft to said drive shaft, 7

substantially non-slipping drive means for transmitting power from said drive shaft to said Wheeied axles,

said drive means comprising an endless belt bighted abo-utsaid drive shaft and about said Wheeled axles,

fair leadmeans comprising a bell-shaped inverted funnel,

said funnel being secured to and supported at its base by said truck assembly whereby said funnel extends upwardly through a floor opening in said main frame and into a housing surrounding said floor opening and extending thereabove,

said fair lead means providing guide means for said belt bighted about said drive shaft and said Wheeled axles and constituting a ball and socket type joinder for said truck assembly and said frame to pivotally connect said truck assembly to said frame.

References Cited in the file of this patent UNITED STATES PATENTS 227,163 Gear May 4, 1880 379,786 Hunt Mar. 20, 1888 1,418,355 Bell et al June 6, 1922 1,770,068 Connors July 8, 1930 1,816,873 Robinson Aug. 4, 1931 2,312,518 Baidwin Mar. 2, 1943 2,589,453 Storsand Mar. 18, 1952 2,903,974 Smith Sept. 15, 1959 2,987,009 Nixon June 6, 1961 

1. IN A VEHICLE FOR SCALE MODEL RAILROADS, THE COMBINATION WITH AN ELONGATED FRAME HAVING A LONGITUDINAL AXIS IN THE DIRECTION OF MOTION OF SAID VEHICLE, A TRUCK ASSEMBLY SUPPORTING SAID FRAME IN SPATIAL RELATION ABOVE TRACK OF SAID SCALE MODEL RAILROAD AND COMPRISING A PLURALITY OF WHEELED AXLES, SAID FRAME HAVING AN OPENING THEREIN EXTENDING THERETHROUGH AND OVER SAID TRUCK ASSEMBLY; OF AN ELECTRICALLY ENERGIZED MOTIVE POWER UNIT COMPRISING A HIGH-SPEED LOW-TORQUE ELECTRIC MOTOR SUPPORTED ON SAID FRAME, A DRIVE SHAFT ROTATABLY JOURNALED ON SAID FRAME, MECHANICAL COUPLING MEANS INTERCONNECTING AN OUTPUT SHAFT OF SAID MOTOR TO SAID DRIVE SHAFT FOR COMMUNICATING MOTIVE POWER THERETO, LINKING MEANS CONNECTING SAID DRIVE SHAFT TO ONE OF SAID WHEELED AXLES FOR TRANSMITTING POWER FROM SAID DRIVE SHAFT TO SAID WHEELED AXLES, SAID LINKING MEANS COMPRISING AN ENDLESS DRIVE BELT 